This class of drugs inhibit the synthesis of cell walls in susceptible microbes by inhibiting peptidoglycan synthesis. Due to their toxicity, their use is restricted to those patients who are critically ill or who have a demonstrated hypersensitivity to the β-lactams. Principally effective against gram positive cocci, they exhibit a narrow spectrum of action. They are the last effective line of defense for cases of Methicillin-resistant Staphylococcus aureus.
Vancomycin is usually given intravenously and can cause tissue necrosis and phlebitis at the injection site if given too rapidly. Indeed pain at site of injection is a common adverse event.